1. Field of the Invention
The present invention relates to Venetian blinds and, more specifically, to an electromagnetic clutch-controlled electric blind.
2. Description of the Related Art
A regular Venetian blind comprises headrail, a bottom rail, a plurality of slats arranged in parallel between the headrail and the bottom rail, an amplitude modulation control mechanism for controlling lifting and positioning of the bottom rail to change the extending area of the blind, a frequency modulation control mechanism for controlling the tilting angle of the slats to regulate the light. The amplitude modulation control mechanism comprises an endless lift cord suspended from the headrail at one lateral side for pulling by hand to lift/lower the bottom rail. The frequency modulation control mechanism comprises a frequency modulation member disposed at one lateral side of the blind for permitting rotation by the user to regulate the tilting angle of the slats. When adjusting the elevation of the bottom rail, the user must approach the blind and pull the lift cord by hand with much effort. Further, because the lift cord is not kept out of reach of children, children may pull the lift cord for fun. In case the lift cord is hung on a child""s head, a fetal accident may occur.
U.S. Pat. No. 5,103,888 discloses a motor-driven blind, which keeps the lift cord from sight. According to this design, a motor is mounted in the headrail or bottom rail, and controlled by a remote controller to roll up or let off the lift cord. The motor is used to control lifting of the lift cord only. When adjusting the tilting angle of the slats, the user must approach the blind and touch-control a tilting control unit. This operation manner is still not convenient.
The present invention has been accomplished to provide an electromagnetic clutch-controlled electric blind, which eliminates the aforesaid drawbacks. It is the main object of the present invention to provide an electromagnetic clutch-controlled electric blind, which controls lifting/lowering of the slats and bottom rail of the Venetian blind as well as tilting of the slats. It is another object of the present invention to provide an electromagnetic clutch-controlled electric blind, which is compact, and requires less installation space. It is still another object of the present invention to provide an electromagnetic clutch-controlled electric blind, which is inexpensive to manufacture. To achieve these objects of the present invention, the electromagnetic clutch-controlled electric blind comprises a blind body formed of a headrail, a set of slats, and a bottom rail, a power drive, the power drive including a reversible motor and electromagnetic clutch means connectable to the motor, an amplitude modulation set coupled to the motor for rotation with the motor to lift/lower the slats to the desired elevation, a frequency modulation set coupled to the motor through the electromagnetic clutch means and adapted for controlling tilting angle of the slats.